1. Field of the Invention
Embodiments of the invention relate to a liquid crystal display and a method of driving the same providing an interior design at low power consumption.
2. Discussion of the Related Art
Liquid crystal displays (LCDs) display an image by controlling light transmittance of a liquid crystal layer with an electric field in response to a video signal. The liquid crystal display is also a flat panel display device having advantages such as a thin profile, small size, and low power consumption. Thus, liquid crystal displays are used in personal computers such as notebook PCs, office automation equipment, audio/video equipment, and the like.
In addition, an active-matrix type liquid crystal display (AMLCD) includes a switching element formed in each liquid crystal cell. Therefore, the active matrix type liquid crystal display is advantageous for displaying a moving picture, because the switching elements can be actively controlled. Further, a thin-film transistor (TFT) is used in the switching element of the active-matrix type liquid crystal display.
In more detail, and with reference to FIG. 1, an active-matrix type liquid crystal display converts digital video data into an analog voltage based on a gamma reference voltage. This supplies the analog data voltage to a data line DL, and at the same time, supplies a scan pulse to a gate line GL. Hence, a liquid crystal cell Clc is charged to a data voltage. For the above-described operation, a gate electrode of a TFT is connected to the gate line GL, a source electrode of the TFT is connected to the data line DL, and a drain electrode of the TFT is connected to a pixel electrode of the liquid crystal cell Clc and an electrode at one side of a storage capacitor Cst. Further, a common voltage Vcom is supplied to a common electrode of the liquid crystal cell Clc.
When the TFT is turned on, the storage capacitor Cst is charged to the data voltage received from the data line DL to keep a voltage of the liquid crystal cell Clc constant. The TFT is turned on when the scan pulse is supplied to the gate line GL. Thus, a channel is formed between the source electrode and the drain electrode of the TFT, and a voltage on the data line DL is supplied to the pixel electrode of the liquid crystal cell Clc. In addition, when an arranged state of liquid crystal molecules of the liquid crystal cell Clc changes by an electric field between the pixel electrode and the common electrode, incident light is modulated.
A liquid crystal display like a liquid crystal display television (LCD TV) generally includes a liquid crystal display panel, a backlight unit, a liquid crystal module including drive circuits with a controller, and a system module including a scaler and a power unit.
Pixels each having a structure illustrated in FIG. 1 are formed on the liquid crystal display panel. The backlight unit is mainly classified into a direct type backlight unit and an edge type backlight unit. In the edge type backlight unit, light sources are installed outside the liquid crystal display panel, and light from the light sources is incident on the entire surface of the liquid crystal display panel using a transparent light guide plate. In the direct type backlight unit, light sources are installed in the rear of the liquid crystal display panel, and light from the light sources is directly incident on the entire surface of the liquid crystal display panel. The direct type backlight unit can increase a luminance and a light emitting surface as compared with the edge type backlight unit because of the plurality of light sources. Therefore, in case of a LCD TV requiring a large-screen liquid crystal display panel, the direct type backlight unit is generally used. The drive circuits include a gate drive circuit, a data drive circuit, a backlight drive circuit, and the like. The controller includes a timing controller, and the like.
The scaler performs image processing on an image received from the outside, so that the image is suitable to be displayed on the liquid crystal module. Further, the scaler generates sync signals synchronized with the image. The power unit includes a driving power supply for driving the liquid crystal module, the scaler, and an audio device and generates a power for driving the liquid crystal display.
However, the related art liquid crystal display has the following problems. First, when the liquid crystal display is used as a TV, for example, and is mounted on a wall, the liquid crystal display has a dark or black appearance when it is not used. Further, many liquid crystal displays are large in size, and thus the liquid crystal display has an unattractive appearance when it is not being used, especially when the liquid crystal display is used in a home, office, work environment, etc. In addition, the amount of power consumption used by the display has greatly increased especially with a trend of large sized and high definition (HD) liquid crystal displays. The high power consumption disadvantageously affects liquid crystal displays.